Suction device for blood diluting pipettes



Dec. 28, 1954 N. DOVAS SUCTION DEVICE FOR BLOOD DILUTING PIPETTES Filed Aug. 5, 1952 INVENTOR. N ICHOLAS 'DOVAS BY 5 AFTER V5) United States Patent SUCTION DEVICE FOR BLOOD DILUTING PIPETTES Nicholas Dovas, New York, N. Y.

Application August 5, 1952, Serial No. 302,687

8 Claims. (Cl. 73425.6)

This invention relates to new and useful improvements in suction devices for blood diluting pipettes.

More particularly, the present invention proposes the construction of an improved suction device which will hold a blood diluting pipette and which can be operated with one hand to draw a definite amount of fluid into the pipette quickly, accurately, conveniently, and safely. Another object of the present invention proposes forming the suction device with a hollow cylinder or barrel and a plunger and providing cam surfaces on the two so that a precise amount of blood can be drawn into a blood diluting pipette merely by twisting or turning the plunger. The pipette can then be quickly and accurately filled with diluting fluid by pulling outwardly on the plunger.

Still further, the present invention proposes constructing the tube and plunger so that two degrees of suction can be obtained by mechanical actions easy to initiate and simple to understand.

As a further object, the present invention proposes arranging the suction device so that it will be compact to carry and efiicient to use.

The present invention further proposes a novel arrangement of a suction device having a cylinder and cam operated sliding plunger with means to hold the cylinder firmly and securely with one hand while the plunger is rotated with the same hand to cause the plunger to be moved through a portion of its suction stroke.

For further comprehension of the invention and of the objects and advantages thereof, reference will be had to the following description and accompanying drawings, and to the appended claims in which the various novel features of the invention are more particularly set forth.

In the accompanying drawings forming a material part of this disclosure:

Fig. 1 is a side view of a suction device for blood diluting pipettes constructed and arranged in accordance with the present invention with a pipette inserted therein and with parts of the device broken away.

Fig. 2 is a view similar to Fig. l with no parts broken away and illustrating the revolved position of the plunger with blood drawn into the pipette to a corresponding degree.

Fig. 3 is a view similar to Fig. 2 but showing the plunger drawn out and the pipette filled the rest of the way with diluting fluid.

Fig. 4 is a side view of a suction device similar to that shown in Figs. 1 to 3 inclusive but illustrating a modification of the present invention.

Fig. 5 is a view similar to Fig. 4 but illustrating a further modification of the present invention.

Fig. 6 is a view generally similar to Fig. 5 but showing the other side and the plunger partly withdrawn from the cylinder.

The suction device for blood diluting pipettes, in accordance with the first form of the invention illustrated in Figs. 1 to 3 inclusive, has a hollow cylinder which may be of plastic or metal but preferably is a transparent glass. The cylinder 15 may be graduated as shown.

A resilient tube or nipple 16, of rubber or flexible plastic, is secured to one end of the cylinder 15 as by having one end of the tube or nipple 16 stretched over or frictionally engaging the cylinder end.

Tube 16 has a passageway 17 through it extending from the cylinder engaging end to the other end. A blood diluting pipette 18 is secured to this tube 16, one end of the pipette being frictionally held in the passageway 17 at the free end of the tube or nipple.

Pipette 18 has a passageway 19 through it and this passageway is connected with the hollow cylinder when the pipette is in the tube or nipple 16 and the tube or nipple is on the cylinder.

A plunger 20 slidably fits in the cylinder 15 extending in the end of the cylinder opposite from that to which the connecting tube 16 is secured. Preferably the plunger is made solid and of material such as ground glass, plastic, or metal. The portion of the plunger slidably fitting into the bore 21 of the hollow cylinder is of a diameter only slightly less than the diameter of the cylinder bore 21 to make a sliding fit therein.

The outer end 22 of the plunger 20 is of a larger diameter and terminates in a flange 23. A resilient gripping band 24, preferably of rubber, fits on the outer end 22 of the plunger adjacent the gripping band 24.

A cam surface 25 is provided on the enlarged outer end portion 22 of plunger 20 adjacent the end of the cylinder 15 receiving the plunger and a like cam surface 26 is provided on this end of the cylinder too. When the plunger is fully inserted into the cylinder the two cam surfaces fit together making a continuous contiguous surface of the outer surface of the cylinder 15 and the outer surface of the enlarged outer end 22 of the plunger 20. Preferably, the plungers outer end 22 is of the same diameter as the outer diameter of the cylinder. The inner end 27 of the plunger 20 does not need to extend to the nipple or tube encased end of the cylinder but may be of any length desired depending on the stroke wanted.

The plunger 20 is not only slidable in the cylinder 15, it is also rotatable therein. Thus, as indicated in Fig. 2 when the pointed free end 28 of the pipette 18 is inserted in a drop of blood on a slide or other surface (not shown) and the plunger 20 rotated in the cylinder, it will be apparent that the cam surfaces 25 and 26 will interact to cause the plunger 20 to be forced rearwardly for a portion of its stroke.

By regulating the slope of the cam surfaces, any predetermined amount of plunger travel can be provided. In the illustration shown in Fig. 2, the cam surfaces on the cylinder and on the plunger are sloped or beveled to such a degree that the suction created by rotating the plunger will be sulficient to draw up the blood to the desired level or mark for either the red or white celled diluting pipette. It will also be apparent that the laboratory technician or other operator can hold the cylinder in one hand to draw up blood into the pipette and can rotate the plunger by turning the grasping ban-d 24 between the thumb and index finger of the same hand drawing up an accurate predetermined amount of blood. Once this amount is drawn into the pipette as by rotating the plunger, the plunger 20 may be pulled out as shown in Fig. 3 to rapidly fill the pipette the rest of the way with blood diluting fluid. This makes the operation of drawing and diluting blood a quick and accurate one.

The modification of the invention illustrated in Fig. 4 is characterized by having a resilient plug 29 with a central opening 30 large enough to receive and frictionally hold the rear end. of a blood diluting pipette. Plug 29 preferably is of the same diameter as the outside diameter of a hollow cylinder or tube 31 and abuts the bottom edge thereof and has an end portion 29 of smaller diameter to frictionally fit within the inner diameter of one end of the tube 31, to retain the plug therein.

Plunger 32 is of substantially the same diameter as the inside diameter of the tube so that the plunger is slidable in the tube through the other end of the tube. The outer end portion 33 of the cylinder is enlarged and of the same diameter as the outer diameter of the tube. A gripping band 34 is secured to this outer end portion 33 of the plunger and cam surfaces 35 and 36 are provided on the cylinder or tube and on the outer end portion 33 of the plunger. Aligned markings 37 are also provided on the cylinder or tube and the outer end portion 33 of the plunger readily to tell when the plunger is bottomed or at the beginning of its stroke.

The modification of the invention illustrated in Figs. 5 and 6 is characterized by the provision of a finger grip 38 secured to the cylinder or tube 39 as by a band 40 clamped to or frictionally held on the tube or cylinder modifications coming within the scope of the invention,

asdefined in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent 1. In asuction tube for blood diluting pipettes, a plunger slidable and rotatable in the tube, said plunger be'mg provided with a cam surface and said tube with a coacting cam surface, said cam surfaces when in contact being adapted to move the plunger through a predetermined portion of its suction stroke in the tube when the plunger is rotated.

2. In a suction tube for blood diluting pipettes, a plunger slidable and rotatable in the tube, said plunger being provided. with a cam surface at the outer end and said tube with a coacting cam surface at the adjacent end, said cam surfaces being arranged so that rotation of the plunger in the tube moves the plunger through a predetermined portion of its suction stroke in the tube, and a resilent gripping band on the plunger adjacent its cam surface for rotating the plunger.

3. In a suction tube for blood diluting pipettes, a plunger slidable and rotatable in the tube, said plunger being provided with a cam surface and said tube with a coacting cam surface, said cam surfaces when in contact being adapted to move the plunger through a predetermined portion of its suction stroke in the tube when the plunger is rotated, and a resilient gripping band on the plunger adjacent its cam surface for rotating the plunger.

4-. A suction device for blood diluting pipettes comprising a hollow cylinder, a plunger slidable in the cylinder, said cylinder having a cam surface at its other end and the plunger having a coacting cam surface abutting the cylinder cam surface when the plunger is fully inserted in the cylinder, said plunger also being rotatable in the cylinder to move the cam surface on the plunger against that on the cylinder and force the plunger partially out of the cylinder and through a predetermined portion of its suction stroke, said plunger being solid and having one end enlarged in diameter with the cam surface of the plunger formed on said end.

5. In a suction tube for blood diluting pipettes, a plunger slidable and rotatable in the tube, said plunger being provided with a cam surface and said tube with a coacting cam surface, said cam surfaces when in contact being adapted to move the plunger through a predetermined portion of its suction stroke in the tube when the plunger is rotated, said plunger being solid and having one end enlarged in diameter with the cam surface of the plunger formed on said end.

6. A suction device for blood diluting pipettes comprising a hollow cylinder, said cylinder having a cam surface at its other end and the plunger having a coacting cam surface abutting the cylinder cam surface when the plunger is fully inserted in the cylinder, said plunger also being rotatable in the cylinder to move the cam surface on the plunger against that on the cylinder and force the plunger partially out of the cylinder and through a predetermined portion of its suction stroke, said plunger being solid and having one end enlarged in diameter with the cam surface of the plunger formed on said end, said enlarged portion of the plunger being of the same diameter as the tube and there being aligning markings on the cylinder and plunger to indicate the aligned position of the cam surfaces and the starting position of the plunger stroke.

7. A suction device for blood diluting pipettes comprising a hollow cylinder having open ends, a plunger slidable through an open end of the cylinder into the cylinder, said plunger having an end portion of enlarged diameter extending from the cylinder, said plunger having a cam surface on the enlarged end portion adjacent the end of the cylinder receiving the plunger and said cylinder having a like cam surface on said end, said cam surfaces being adapted to move the plunger through a predetermined portion of a suction stroke in the cylinder when the plunger is rotated, said enlarged portion of the plunger being of the same diameter as the cylinder, there being aligning markings on the cylinder and the plunger to indicate the aligned position of the cam surfaces, and a gripping band on the enlarged end of the plunger for rotating it in the cylinder.

8. In a suction tube for blood diluting pipettes, a plunger slidable and rotatable in the tube, said plunger being provided with a cam surface and said tube with a coacting cam surface, said cam surfaces when in contact being adapted to move the plunger through a predetermined portion of its suction stroke in the tube when the plunger is rotated, and a finger grip on the tube tov hold it as the plunger is rotated.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,433,075 Gottlieb Oct. 24, 1922. 2,358,936 Mathis Sept. 26, 1944 FOREIGN PATENTS Number Country Date 882,339 France Mar. 1, I943 

